Analyzer for comparing the response of an organism to a reference pattern

ABSTRACT

A system for testing the reaction of a human subject to a test stimulus for ascertaining the fitness of the human subject for performing a specific task, in particular, the driving of an automobile under the influence of alcohol. The test utilized in the preferred embodiment of the invention requires a human subject to monitor the magnitude of a quantity (such as the length of a line) which changes at a nonuniform predictable rate utilizing information provided by minimal cues, in particular, a pair of flashing lights which indicate whether the rate of change is being overestimated or underestimated. Circuitry for building a test device, as well as interlocking such a device with the ignition system of an automobile, are also disclosed.

United States Patent [1 1 Hill Feb. 26, 1974 ANALYZER FOR COMPARING THERESPONSE OF AN ORGANISM TO A Primary Examiner-Alvin H. Waring REFERENCEPATTERN Attorney, Agent, or Firm.loseph D. Pannone; David 1 M. W ;M'1tD. B rt] [75] Inventor: Lyle M. Hill, Portsmouth, RI. arren l on a [73]Assignee: Raytheon Company, Lexington, [57] ABSTRACT Mass- A system fortesting the reaction of a human subject [22] Filed: Sept. 11 1972 to atest stimulus for ascertaining the fitness of the human subject forperforming a specific task, in par- PP 287,960 ticular, the driving ofan automobile under the influence of alcohol. The test utilized in thepreferred em- 52 11.5. CI. 340/52 R, 340/279 bOdimeI of invemkm requiresa human Subject 51 Int. Cl. G08b 21/00 the magnitude of a quantity (Suchas the [58] Field of Searchm 340/63 64, 52 R 52 F 279 length of a line)which changes at a nonuniform predictable rate utilizing informationprovided by mini- [56] References Cited mal cues, in particular, a pairof flashing lights which indicate whether the rate of change is beingoveresti- UNITED STATES PATENTS mated or underestimated. Circuitry forbuilding a test 3,559,205 1/1971 Colby 340/52 R device, as we asinterlocking such a device with the 33;; ignition system of anautomobile, are also disclosed. 2:625:594 1/1953 Mathis 340 279 29Claims, 6 Drawing Figures START I" SWITCH PATTERN GENERATOR M i l i-l T56 94 INDICATOR 22 TURN PASS LE INDICATOR 7 a ,INDICATOR 60 90 9COMPARATOR L INTEGRATOR LOGIC 26 j 66 76 RESPONSE SIGNAL 5:

GENERATOR 85 PULL BACK FAIL 34 INDICATOR INDICATOR 32 PUSH 64 FORWARD 60\v, mule/non 46 PAIEN'IEI] FEB26 I974 SHEET 2 IIF 4 GENERATOR (SECONDCOORDINATE) Eo sTART 22 h SWITCH A. I I5ATTERN GENERATOR I I N ggyMULTIPLEXING I I GENERATOR SWITCH I I I I /278 25 3 I I 250 274/ 260 I II 282 r"-'--- I 36 CLOCK V ou T UP/DOWN D I I I I c N ER COUNTER A I I1I I 268 Z76 I I I I I 252 258 277 DowNI 262 I I I 0 0 I T l I I I I IMULTIPLEXING I I SWITCH I I 256 I I I I I GENERATOR I FIRST COORDINATE)I l I TO sTART I :3 SWITCH I02 I I l I I I I I I I I l PATENIEII EW I3,794,968

SHEET l 0F 4 2 04 B TIMER p304 ZOMIN. ANALYZER I SYSTEM 3/9 RESET =T C/36 303 3/0 REsET 3 BIT COUNTER M35 SINGLE TIMERSWITCH PULSE oPENsAFTER[GENERATOR 3/2 3MIN. 298

IGNITION KEY SWITCH F/G 5 294 fl RESET 286 l cIf sE IA/ I T C H SW'TCHIGNITION IRCUIT IO MIN. RUN C T O EN3/6 I FLASHER 3/8/OI CIRCUIT 200 204EMERGENCY BY PASS l IFNKI GET\IE REO R I E5998 I 4 i 3\20 332 I I IINTEGRATOR i COMPARATOR I F/G 6 --26/I ANALYZER FOR COMPARING THERESPONSE OF AN ORGANISM TO A REFERENCE PATTERN BACKGROUND OF THEINVENTION This invention relates to systems for testing the humanresponse to a specific test situation for determining the fitness of aperson for performing a related task. In particular, a test situationrelated to the driving of an automobile is provided for predicting thefitness of a human subject under the influence of alcohol for driving anautomobile.

Drunkenness by persons in public places has presented a much publicizedhazard to the general public, particularly in those situations wherein aperson having diminished capabilities due to excessive quantities ofalcohol in his blood attempts to drive an automobile. Indeed, drunkendriving is a primary cause of death on the highways. In addition toalcohol, other factors such as drugs, sickness, or excessive fatigue mayresult in impaired fitness for performing specific tasks such as theoperation of industrial machinery and automobiles, in which cases harmmay result to the person himself as well as to other people.

While it has long been recognized that the aforesaid harm may be avoidedby requiring people to desist from the operation of machinery while theyare in a state of diminished capability, the problem has been everpresent that there is no convenient and accurate means for determininghow well such persons can operate the machinery or perform other tasksrelated thereto.

With reference to a related matter, it is noted that the response of aperson in a testing procedure may be beneficial in teaching himself toimprove, this being a particular problem situation arising in therapyfrom serious illness such as a stroke causing partial paralysis of apart of the body.

SUMMARY OF THE INVENTION The aforementioned problems are overcome andother advantages are provided by a system, in accordance with theinvention, which provides for a device that may be manipulated by ahuman subject, such as the turning of a knob, and an indicator foreliciting a sensory perception by the person for warning the person howwell he is performing. There is also provided a comparator, preferablyin the form of an electrical circuit, which compares the pattern of thesubjects response to a reference pattern and, in accordance with thecomparison, energizes the warning indicator. In a preferred embodimentof the invention, two light sources serving as the indicator areutilized with a knob, one light source glowing brightly when the knob isturned too slowly, the other light source glowing brightly when the knobis turned too rapidly, with both light sources glowing dimly when theknob is turned at a proper rate. The reference pattern, in the preferredembodiment, is provided by a predetermined turn rate program withrespect to the turning of the knob, unknown to the person being tested,which must be followed closely to pass the test. Such a turn rateprogram is conveniently provided by an electrical circuit comprising aresistor and capacitor wherein the transient response of the circuitrepresents the pattern of values for either the knob position or therate of turn of the knob. To implement the aforesaid relationship of thecircuit transient response to the rate of turning of the knob, atransformation (in a mathematical sense) of the subjects response isprovided by an integrator circuit, in one embodiment of the invention,which is coupled between the knob and the comparator. Other patterns maybe utilized such as a sinusoidal pattern which is readily provided by anoscillatory electrical circuit. The changing magnitude of the electricalsignal of the aforesaid transient response bears an apparent similarityto the radius of curvature of a roadway wherein a driver would berequired to turn at an ever increasing rate and then to straighten outat a decreasing rate of turning until the turn in the roadway iscompleted.

The testing as provided by the preferred embodiment of the invention hasshown an excellent correlation between the performance of a humansubject under test and his performance in actually driving an automobilewhile under the influence of alcohol. Means are also disclosed forconnecting the electrical circuitry of the test device with the ignitionsystem of a vehicle such as an automobile or an aircraft to prevent useof such vehicle until the operator is suitably fit to operate thevehicle. Other sensors and tasks may be utilized such as the tracking ofa musical tone in response to other tones which indicate how the trackedtone is to vary. Tactile stimulation may be utilized wherein a forceapplied to one limb of a person indicates how a second limb is torespond.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned objects and otherfeatures of the invention are explained in the following descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is a block diagram of a reaction analyzer system in accordancewith the invention;

FIG. 2 is a pictorial representation of a roadway useful in showing ananalogy between a changing radius of curvature and a pattern utilized inthe reaction analyzer of FIG. 1;

FIG. 3, partially in schematic form and partially in block diagrammaticform, shows electrical circuitry utilized in a preferred embodiment ofthe invention according to FIG. 1;

FIG. 4 is a block diagram of an alternative form of pattern generatorutilized in FIG. 1;

FIG. 5 is a diagram of a vehicular interlock system including thereaction analyzer system of FIG. 3; and

FIG. 6 is a diagram of an alternative embodiment of a response signalgenerator of FIG. 3 showing a rate control.

DESCRIPTION OF THE PREFERRED EMBODIMENT being tested, and a comparator32 for comparing signals on lines 34 from the generator 26 with signalson lines 36 from the pattern generator 22. With reference to FIG. 2, anautomobile 38 is being driven along a roadway 40 having a varying radiusof curvature as is indicated by each of the radii 42 drawn from a commonpoint 44 to an edge of the roadway 40. It is apparent that as theautomobile 38 approaches a curve in the roadway 40, the automobile 38must negotiate a path of decreasing radius of curvature until a minimumradius of curvature is reached, after which the radius of curvaturesteadily increases as the automobile 38 approaches a straighter portionof the roadway 40. In a similar manner, the signal on line 36 has, in apreferred embodiment of the invention, a waveform which becomessuccessively more positive during a first interval of time whereupon thewaveform isaltered in the opposite sense to become successively morenegative during a second interval of time.

For purposes of analyzing the capabilities of the person 30 for drivingthe automobile 38 along the roadway 40, an adequate simulation of thedriving conditions is implemented by generating the waveform of thesignal on line 36 from a succession of transient responses of aresistor-capacitor (R-C) circuit such that the waveform increases at anexponentially decreasing rate in a first direction and, thereafter,decreases at an exponentially decreasing rate in the opposite direction.

For thorough testing of the person 30, it may be desirable to utilize amore complex test situation in which responses of the person 30 are tobe provided in a plurality of coordinates, the handle 24 providing twosuch coordinates, one of which is a rotation of a knob 46 and the secondbeing the pushing and pulling of a shaft 48 which supports the knob 46and is pivoted about pivot 50 to a base 52 of the handle 24.Potentiometers, not shown, may be built into the handle 24 such that onepotentiometer connected between the knob 46 and the shaft 48 provides anelectrical signal indicating an angle of rotation of the knob 46 while asecond potentiometer connected to the pivot'50 provides an electricalsignal representing an angle of pivot of the shaft 48 relative to thebase 52. These two signals are communicated via the lines 28 to thegenerator 26 which, in turn, converts these signals either by a linearscaling or via a nonlinear relationship such as that ofa sine or cosinefunction to appear as the signals on the respective lines 34. In a twocoordinate system, the pattern generator 22 generates a pair of signalson the lines 36, each of which is compared to the corresponding signalon the lines 34 by the comparator 32.

The system further comprises six indicators, namely, a turn rightindicator 54, a turn left indicator 56, a push forward indicator 58, apull back indicator 60, a pass indicator 62, and a fail indicator 64, acombiner 66 comprising three components, namely, an exclusive OR gate68, an exclusive OR gate 70 and an OR gate 72, an integrator 74 forsumming together successive outputs from the combiner 66, and a logicunit 76 which in response to the output of the integrator 74 energizesthe pass and fail indicators 62 and 64. The turn right and turn leftindicators 54 and 56 show the person how well he is turning the knob 46while the push forward and pull back indicators 58 and 60 show theperson how well he is pivoting the shaft 48. For analysis based on atesting of the person 30 in a single coordinate, such as by means of aturning of the knob 46, only the turn right and turn left indicators 54and 56 are utilized.

The comparator 32 operates in the following manner for accomplishing ananalysis in only one dimension. When the signal on line 36 is greaterthan the signal on line 34, a high voltage appears on line 78 and a lowvoltage on line 80, this energizing the turn right indicator 54 andde-energizing the turn left indicator 56. The turn right and the turnleft indicators 54 and 56 may be visual indicators such as lightedlamps, aural indicators such as a high-pitched tone for turn right and alow pitched-tone for turn left, or tactile indicators such as a device(not shown) which applies pressure to the foot of the person 30 orpinches his skin. In the event that the signal on a line 36approximately equals the signal on the corresponding line 34, then thesignals on lines 78 and 80 may have equally high values of voltage orequally low values of voltage to indicate a good response by the person30, the two indicators 54 and 56 being energized in the former situationwhile in the latter situation both indicators would be deenergized. Witheither the former or latter situation, the exclusive OR gate 68 wouldprovide a signal on line 82 having a logic state of 1 only when theresponse of the person 30 is in error, this corresponding to aninequality of the signals on the lines 34 and 36, the exclusive OR gate68 providing a signal on line 82 having a logic state of 1 during a goodresponse of the person 30, this being an approximate equality of thesignals on the lines 34 and 36.

For the two coordinate situation, the comparator 32 operates in asimilar manner with a second pair of signals on the lines 34 and 36 foroperating the indicators 58 and 60. Thus, in accordance with a signalhaving a logic value of 1 on either line 84 or line 86, the exclusive ORgate ovides a signal on line 88 having a logic value of 1. The ORcircuit 72 provides a signal having a logic state of l on line 90 inresponse to logic 1 signals on either line 82 or line 88 or on both ofthese lines. Thus, the logic 1 signal on line 90 indicates a failure ofthe person 30 to properly turn the knob 46 or pivot the shaft 48, or acombination of these failures throughout the interval of time duringwhich the logic 1 state persists on the line 90. Alternatively, the ORgate 72 may be replaced with a summing amplifier (not shown) such thatthe voltage on the line 90 is doubled when a failure of response by theperson 30 is simultaneously present on both of the coordinates, namely,the turning of the knob 46 and the pivoting of the shaft 48. Theintegrator 74 provides a signal on line 92 which is the integral of thewaveform of the signal appearing on line 90. Thusfif a logic state of 1is present on line 90 for an extended period of time, the signalon line92 builds up rapidly, whilelif the logic state of 1 is presentinfrequently or for only short periods of time, then the signal on line92 rises at a relatively low average rate. Thus, the value of the signalon line 92 is a measure of the error experienced by the person 30 intrying to track the pattern of the signal or signals on the lines 36.Alternatively, the OR gate 72 may be replaced with an OR gate (notshown) in which case the signal on line 92 will represent the amount ofsuccess experienced by the person 30 in tracking the signal or signalson line 36. The logic unit 76 energizes the pass indicator 62 inresponse to a signal on line 94 which signal indicates the terminationof the test pattern provided by the pattern generator 22. However, ifthe magnitude of the signal on line 92 indicates an excessive amount oferrors on the part of the person 30, then the logic unit 76 gates outthe signal on line 94 and energizes the fail indicator 64.

It is apparent from the comparison of the FIGS. 1 and 2, that in thereal-life situation of FIG. 2, a driver of the automobile 38 ispresented with a view of the'roadway 40 as it actually appears, whilethe person 30 of FIG. 1 knows nothing about the highway or the analogoustest pattern of the pattern generator 22 than that provided by theindicators 54, 56, 58 and 60. Assuming that lighted lamps are used forthese indicators, the person 30 would only see the lighting of a lampand the extinguishing of another lamp in response to his turning of theknob 46 and his pushing of the shaft 48. Thus, the system requires asignificant amount of concentration by the person and a significantamount of memory of his prior experience in attempting to feel out thenature of the curve traced by each portion of the waveforms of thesignals on the lines 36. It is the coordination of his powers ofconcentration with his motor skills in manipulating the handle 24 thatserve to test his reaction to the test pattern of the pattern generator22 under the influence of various debilitating factors such asintoxication, drug addiction, sickness or fatigue.

Referring now to FIG. 2, there is shown a system 20A which is animplementation of the system 20 of FIG. 1 for a single coordinate inwhich only the knob 46 is to be manipulated by the person 30. FIG. 3shows the logic unit 76 in block diagram form while the patterngenerator 22,'the comparator 32, the generator 26 and the integrator 74are shown via electrical schematic diagrams. In lieu of the combiner 66of FIG. 1, there is provided in FIG. 3 a combiner 66A which functions ina manner analogous to the combiner 66 of FIG. 1 but has a somewhatsimplified electrical circuit.

The pattern generator 22 of FIG. 3 is seen comprising a waveform circuit96, a switch circuit 98 and a timer 100, the timer 100 being connectedby an external start switch 102, seen also in FIG. I, which serves thedual functions of starting the timer 100 and the pattern generator 22 aswell as providing power from a battery 104 to the system 20A. Thewaveform circuit 96 comprises two resistors 106 and 108 and a capacitorll0.The switch circuit 98 comprises three transistors 112, 114, and 116,the transistor 116 having a collector electrode 118, a base electrode120 and an emitter electrode 122, the transistor 114 having a collectorelectrode 124, a base electrode 126 and an emitter electrode 128, andthe transistor 116 having a collector electode 130, a base electrode 132and an emitter electrode 134. The transistors 112 and 116 are of theNPN-type while the transistor 114 is of the PNP-type. The capacitor 110is connected between ground 136 and a junction of the two emitterelectrodes 122 and 128. The base and collector electrodes of thetransistor 112 are coupled respectively via resistors 106 and 108 to aterminal designated by the letter A, the terminal A being coupled to thepositive terminal of the battery 104 during operation of the system 20Avia the start switch 102. The base electrodes 120 and 126 are connectedtogether and to the collector electrode 130. The emitter terminal 134 ofthe transistor 116 is connected to ground 136 while the collector 124 ofthe transistor 114 is coupled to ground 136 via a resistor 138. A biasvoltage for the base electrode 132 of the transistor 116 is provided byresistors 140 and 142 which are joined together at the cathode electrodeof a zener diode 144,

the anode electrode of the zener diode 144 being con-. nected to thebase electrode 132 of the transistor 116.

The timer comprises a resistor 146 and a capacitor 148 which areserially connected between the terminal A and ground 136. When theterminal A is coupled via the start switch 102 to the battery 104,current flows by the resistor 146 into the capacitor 148 with the resultthat the voltage across the capacitor 148 builds up in accordance withthe well-known R-C transient response. Line 150, which connects with thejunction of the resistor 146 and capacitor 148, provides a timingvoltage.

In operation, the pattern generator 22 provides a signal voltage on line36 which is to be tracked by the person 30 of FIG. 1, the signal voltageon line 36 having the form of, in the preferred embodiment of theinvention, an R-C circuit transient response in which the voltage isincreasing followed by such a transient response in which the voltage isdecreasing. The first transient begins when the start switch 102 isoperated to energize the timer I00, and the second transient begins whenthe timing signal voltage on line 150 reaches a predetermined value.During the first of these two transients, the zener diode 144 is in astate of nonconduction due to the low value of voltage present on theline 150. Thus, the transistor 116 is nonconducting with the result thatthe transistor 1 12 conducts current via resistor 108 into the capacitorthereby charging the capacitor 110 at a rate related to the value of theresistor 108. When the value of the voltage on the line reaches theaforesaid predetermined value, the zener diode 144 begins to conductbase current into the transistor 116 with the result that current nowflows via the resistor 106 through the transistor 116 thereby reducingthe magnitude of the voltage at the collector electrode 130.Accordingly, the transistor 114, which was previously in a sate ofnonconduction, is now placed in a state of conduction and conductscurrent from the capacitor 110 through the resistor 138 therebydischarging the capacitor 110 at a rate related to the value of theresistor 138. The discharging of the capacitor 110 continues until theswitch 102 is returned to the OFF condition. In the OFF condition, thestart switch 102 discharges the capacitor 148 of the timer 100 via aresistor l'52 so that the timer 100 is now ready for the next test ofthe responses of the person 30 of FIG. 1.

The comparator 32 comprises two transistors 154 and 156, the transistor154 comprising a collector electrode 158, a base electrode and anemitter electrode 162, and the transistor 156 comprising a collectorelectrode 164, a base electrode 166 and an emitter electrode 168. Theemitter electrodes 162 and 168 are connected together and coupled toground 136 via a I resistor 170. The two transistors 154 and 156 form adifferential circuit in which the conduction of current in one of thetwo transistors raises the voltage drop across the resistor 170 therebytending to diminish the amount of current in the other transistor. Alightemitting diode is placed in the collector circuit of each of thetransistors 154 and 156. The light-emitting diode connecting with thetransistor 154 serves as the right turn indicator 54 of FIG. 1 and willbe referred to as diode 54A with reference to FIGS. 3, while thelightemitting diode connected to the transistor 156 serves as the turnleft indicator 56 of FIG. 1 and will be referred to as diode 56A withreference to FIG. 3. Current flows from the terminal A through thediodes 54A and 56A and the transistors 154 and 156 into the resistor 170and then to ground 136. The current in the transistor 154 is controlledvia base current applied to the base terminal 160 via a resistor 172which is connected to the line 36. I

Current flow in the transistor 156 is controlled via a voltage providedto the base terminal 166 by the generator 26 which has a potentiometer174 coupled to terminal A via a resistor 176. The potentiometer 174 ismechanically coupled via line 178 to the knob 46 so that a turning ofthe knob 46 by the person 30 of FIG. 1 positions the tap on thepotentiometer 174 thereby adjusting the voltage applied to the baseterminal 166. When the person 30 is very accurately tracking the signalvoltage on line 36, the current in the two transistors 154 and 156 aresubstantially equal so that equal current flows through the two diodes54A and 56A with the result that these two diodes glow withsubstantially equal intensity, such intensity being moderately bright,moderately dim, or virtually non-existant, depending upon the magnitudeof the resistor 170. Accordingly, a condition of good tracking may berepresented in the system A by equal intensity or the cessation of anyglowing by selecting the requisite current flow in these diodes 54A and56A by a suitable choice of value of resistance for the resistor 170.

in the event that the person in FIG. 1 has not turned the knob 46 asufficient amount to the right, then the voltage provided by thepotentiometer 174 is lower than the voltage at the base electrode 160 ofthe transistor 154 with the result that more current flows through thediode 54A than the diode 56A, hence, the diode 54A glows brightly whilethe diode 56A is extinguished thereby providing the desired indicationshowing that the knob 46 is to be turned more to the right. In the eventthat the person 30 has turned the knob 46 too far to the right, thevoltage provided by the potentiometer 174 is raised a value higher thanthe voltage appearing at the base electrode 160 and the diode 56A glowsbrightly while the diode 54A is extinguished, this indicating that theperson 30 should turn the knob 46 towards the left.

The combiner 66A comprises four transistors 180, 182, 184 and 186, atransistor 180 comprising a collector electrode 188, a base electrode190 and an emitter electrode 192, the transistor 182 comprising acollector electrode 194, a base electrode 196 and an emitter electrode198, the transistor 184 comprising a collector electrode 200, a baseelectrode 202 and an emitter electrode 204, and the transistor 186comprising a collector electrode 206, a base electrode 208 and anemitter electrode 210. The transistors 180 and 182 are type PNP and thetransistors 184 and 186 are type NPN. The transistor 186 is coupled viaits emitter electrode 210 to the integrator 74 such that current flowingthrough the transistor 186 also flows through a potentiometer 212 and acapacitor 214 which form a part of the integrator 74. The capacitor 214builds up an electrical charge which is equal to the integral of thecurrent flowing therethrough and thus serves as the electrical elementwhich performs the integration for the integrator 74. The collectorterminal 200 of the transistor 184 is coupled via a resistor 216 to theterminal A and via a second resistor 218 to the base electrode 208 ofthe transistor 186. Thereby, a signal appearing at the base electrode202 of the transistor 184 is amplified,

withthe amplified signal appearing at the collector electrode 200 andcoupled via the resistor 218 to the base electrode 208. The transistor186 applies a current to the capacitor 214 proportional to the signal atthe base terminal 208 and thereby provides a signal on line 220 which isthe integral of the signal appearing at the base electrode 202.

The transistor 180 is connected via its emitter termina] to a resistor222 which provides a flow of current from the terminal A to thetransistor 180. The transistor 180 is in turn connected via itscollector terminal to the emitter terminal of the transistor 182 which,in turn, is connected via its collector terminal 194 to a re- I sistor224, the resistor 224 being connected to ground 136. The base electrode190 of the transistor is directly connected to the collector electrode158 of the transistor 154, and the base electrode 196 of the transistor182 is directly connected to the collector electrode 164 of thetransistor 156.

In operation, the signals which energize the diodes 54A and 56A of thecomparator 32 also energize the transistors 180 and 182 of the combiner66A. When the voltage at the collector electrode 158 rises, thiscorresponding to a condition of diminished current in the diode 54A anddiminished illuminance thereof, the voltage across the base-emitterjunction of the transistor 180 is reduced providing for diminishedcurrent through the transistor 180. Similar comments apply to therelationship between the illuminance of the diode 56A and the transistor182. The values of resistance of resistors 222 and 224 are selected suchthat when the values of voltage applied to the base electrodes and 196are substantially equal, a maximum current flows through the transistors180 and 182 providing a maximum voltage drop across the resistor 224.When the diode 54A is glowing and the diode 56A is extinguished, thevoltage applied to the base electrode 190 is lower than the voltageapplied to the base electrode 196 with the result that current enteringthe transistor 180 at the emitter electrode 192 flows through the baseelectrode 190 while the collector electrode 188 appears to be opencircuited, there being no current flowing through the transistor 182since the base-emitter junction thereof is back biased. Thus, no currententers the resistor 224 from the collector electrode 194 with the resultthat a minimum voltage drop appears across the resistor 224. Similarly,when the diode 56A is glow ing and the diode 54A is extinguished, and,accordingly, a minimal current flows through the transistor 180 while amaximum voltage drop appears between its collector and emitterelectrodes, the voltage drop across the resistor 224 is again at arelatively low value. A low voltage drop across the resistor 224 resultsin a relatively high value of voltage appearing at the collectorelectrode 200 while a relatively large voltage drop across the resistor224 results in a minimum value of voltage appearing at the collectorelectrode 200. Thus, during periods of time when either one of thediodes 54A or 56A are illuminated, but not when both of these diodes areilluminated, the transistor 186 applies a relatively large current tothe integrator 74 with a result that the capacitor 214 is being charged.

The total charge accumulated by the capacitor 214 is related to theamount of time that only one of the diodes 54A or 56A is flowing or,correspondingly, the amount of time that the person 30 of FIG. 1 is inerror in his attempt to track the voltage waveform appearing on line 36.The potentiometer 212 is wired so that its tap is connected to oneterminal thereof so that if functions as a variable resistor, theposition of the tap controlling the rate at which the capacitor 214 ischarged in response to the voltage appearing at the collector 200 of thetransistor 184. The potentiometer 212 has been labeled a difficultycontrol" in FIG. 3 since a rapid rate of charge will energize the failindicator 64 of FIG. I even with minimal errors in the part of theperson 30 while a low rate of charge results in an energization of thefail indicator 64 only in the event of an extensive interval of failureon the part of the person 30.

The integrator 74 further comprises a resistor 226 connected betweenground 136 and emitter electrode 228 of a transistor 230, the collectorelectrode 232 thereof being connected to the line 220 while the baseelectrode 234 thereof is connected to the logic unit 76 along line 236in a manner to be described, the lines 236 and 220 being included withinthe line 92 shown in FIG. 1. In response to a signal on line 236, thetransistor 230 is made to conduct current through the capacitor 214thereby discharging the capacitor. In the absence of the signal on line236, the capacitor 214 retains its charge. A section of the start switch102 is serially connected with a resistor 238 between the line 220 andground I36 for discharging the capacitor 214 when the system 20A isturned off at the completion of a test.

The logic unit 76 comprises two threshold detectors 240 and 242 and anAND gate 244. The threshold detector 240 is responsive to the signal online 150 and has an output on line 246 connected to the AND gate 244.The threshold detector 242 is responsive to the signal on line 220 andhas an output on line 248 which is connected to a complemented input ofthe AND gate 244. The pass indicator 62 of FIG. 1 is provided for inFIG. 3 by a lamp 62A which may be a light-emitting diode, and the failindicator 64 of FIG. 1 is provided for in FIG. 3 by a lamp 64A. Thethreshold detectors 240 and 242 may utilize circuitry such as awell-known comparator circuit or a Schmitt trigger-type circuit whereinthe output signals on the lines 246 and 248 are either of a' highvoltage or a low voltage depending on whether the voltages on the lines150 and 220 are, respectively, above or below a predetermined value ofthrehold. The threshold detector 240 provides the high value of voltagecorresponding to a logic state of I on the line 246 when the timingsignal on line 150 has reached a value indicating that the test intervalis completed, and the threshold detector 242 provides the high voltagecorresponding to a logic state of 1 on the line 248 when the voltage online 220 has risen to a value corresponding to a failure on the part ofthe person 30 of FIG. 1. When the person 30 is performing the testsatisfactorily, a low voltage or logic state of appears on the line 248so that upon the first appearance of a logic state of l on line 246, theAND gate 244 provides a high voltage or logic state of 1 on line 236which energizes the lamp 62A and energizes the transistor 230 todischarge the capacitor 214 thereby insuring that the voltage on theline 220 will not rise to a value indicating a failure; thus, if thepass lamp 62A is illuminated, a logic state of 1 will not appear on line248 for illuminating the fail lamp 64A. In the event that the person 30performs with excessive errors such that the voltage on line 220 risesto a sufficient value to trigger the threshold detector 242, the logicstate of 1 appears of l appearing on line 246 at the termination of thetesting interval is not communicated tot e line 236, thereby insuringthat the pass lamp 62A remains extinguished.

Referring now to FIG. 4, there is seen an alternative embodiment of thepattern generator 22 of FIG. 1, here shown having two sections, eachcomprising a generator 249, one for each coordinate. Each generator 249comprises a generator 250 of random numbers, a clock 252, twomultiplexing switches 254 and 256, a counter 258, and UP/DOWN counter260, a digital-to-analog converter to be referred to hereinafter as D/A262, and a circuit 264 comprising a resistor 266 and a capacitor 268which function in a manner analogous to the resistor 108 and capacitor110 of FIG. 3 in providing an R-C transient response waveform. Bothgenerators 270 are seen coupled to the start switch 102 in a mannerconforming to that of FIG. I, and each is provided with an output alonga line 36 as is seen also in FIG. 1.

The operator of each of the generators 249 is the same so that only'oneof them need be described. The generator 250, of random numbers, isdriven by clock signals on line 272 provided by the clock 252, and inresponse thereto, provides multibit numbers on lines 274 to themultiplexing switches 254 and 256. The clock 252 also provides clocksignals to the counter 258 via line 256 as well as to the UP/DOWNcounter 260 as is shown in the figure by terminal C. A set of lines 277connects from the various cells or stages of the counter 258 to providesquare wave signals of differing pulse repetition frequencies, thefrequency of each such signal on one of the lines 277 being double thesignal on the adjacent line 277, to the multiplexing switches 254 and256. A binary number on the lines 274 selects a particular line 277 tobe transmitted along the output lines 278 and 280 respectively of themultiplexing switches 254 and 256. Thus, square waves of differingfrequencies appear at regular intervals on the lines 278 and 280,corresponding to the intervals of the clock signals on the line 272. TheUP/DOWN counter 260 comprises steering logic which in response to thepresence of a signal on line 278 counts UP, and in response to thepresence of signals on line 280 counts DQwN with a count beingregisteredfor each logic state of 1 appearing on the line 278 and foreach logic state of 1 appearing on the line 280. The output of theUP/DOWN counter 260 appears on lines 282 and is applied to D/A 262 whichconverts the digital number at the output of the counter 260 to ananalog voltage, the analog voltage being applied to the circuit 264. Theanalog voltage being applied to the circuit 264 has the form of astair-case voltage which increases and decreases in a random fashion asprovided by the random number generator 250, with the intervals ofchange in these steps being multiples of the intervals of the clockpulses on the line 272. The signals provided by the clock 252 aresuitably delayed from each other so that the counter 258 changes stateafter the generator 250 has addressed the multiplexing switches 254 and256. The multiplexing switch 254 operates on a different set ofaddresses than does the multiplexing switch 256 so that only one ofthese switches accepts an input from a line 277 at a time. The resultantwaveform appearing on line 36 in FIG. 4 is thus similar to the waveformappearing on line 36 of FIG. 3 except that, in FIG. 4, a

succession of transient responses appears of which the amplitudes anddirections are provided in a random manner. The pattern generator 22 ofFIG. 4 provides a more complex testing pattern than that of FIG. 3 inthat the person being tested can learn to operate the system 20 butcannot learn a particular pattern since they are provided in a randommanner.

The systems 20 of FIG. 1 and 20A of FIG. 3, in addi tion to being usefulfor analyzing a reaction of a human subject, may be interlocked directlywith the ignition system of an automobile to prevent its use by a personwho fails the test. Special consideration need be given to the buildingof these systems when the intended use is within an automobile due tothe high values of electromagnetic noise which are generated by anautomobile ignition system. In particular, it has been noted that intests of these systems and of other devices constructed of standarddigital components conducted in the vicinity of an operating automobileignition system, the devices constructed of the standard digitalcomponents malfunctioned while the system utilizing the circuitrydisclosed in FIG. 3 operated successfully in the environment of anoperating automobile ignition system. It is deemed advisable to avoidthe use of bistable flip-flop devices which are set to be triggered by anarrow pulse or the leading edge of a pulse since the presence of anoise pulse provided by radio frequency interference may trigger such abistable flip-flop. In contradistinction, it is noted that no suchcircuitry is utilized in the embodiment of FIG. 3. Each circuit shown inFIG. 3 will maintain its output voltage only as long as its inputvoltage is present, and a noise pulse at the input to any one circuitcan result in no more than a noise pulse at the output of that circuit.Such is the case with the threshold detectors 240 and 242 since theycomprise either a directly coupled comparator circuit or Schmitttrigger-type circuit without the use of capacitive coupling. And this isalso the case with the switch circuit 98, the comparator 32 and thecombiner 66A each of which utilize directly coupled circuitry ratherthan capacitively coupled circuitry. Furthermore, these circuits areinherently resistant to the presence of interfering noise pulses; forexample, the line 150 is incrementally grounded via the capacitor 148which shorts out sudden increments in the signal such as an-interferingnoise pulse, and in a similar way the lines 36 and 220 are incrementallygrounded respectively via capacitors 110 and 214.

Referring now to FIG. 5 there is seen an interlock system 284 forcoupling the analyzer A of FIG. 3 to the ignition circuit 286 and to theflasher circuit 288 of an automobile or other vehicle. As seen in bothFIGS. 3 and 5, the system 20A has in addition to the aforementionedground terminal 136 and terminal A, the terminals B and C which areconnected respectively to the lines 236 and 248 of FIG. 3. Theseterminals are utilized for connecting the system 20A to the interlocksystem 284 as shown in FIG. 5.

The interlock system 284 comprises two relays 290 and 292, two timerswitches 294 and 296, two diodes 298 and 300, a pulse generator 302which generates a single pulse a moment after being energized with powerfrom terminal A, a timer 304 which has been given a running time of 20minutes in this embodiment of the invention, a counter 306 which has athree-bit capacity in this embodiment of the invention, an AND gate 308having one of its inputs complemented, and an OR gate 3 and, if hepassesthe test, the logic state b'f'i appearing at the terminal B istransmitted via the diode 298 to a switch 314 which is operated by theignition key. Upon seeing that he has passed the test, as indicated bythe lighting of the pass lamp 62A of FIG. 3, the opera tor then turnsthe ignition key thereby closing the switch 314 with the result thatthehigh voltage representing the logic state of l at the terminal B nowenergizes the relay 290. The energization of the relay 290 closes a pairof contacts to the ignition circuit 286 for starting and running theautomobile.

In the event that the automobile were to stall, or in the event that theoperator turned the motor off for a few minutes while refueling at agasoline station, it is desirable that upon restarting the automobile,he should not be required to take the test of the analyzer system 20A.Accordingly, the energization of the relay 290 closes a pair of contactsin the circuit of the timer switch 294 which applies voltage from asuitable source such as a battery 316 to the reset terminal of the timerswitch 294, thereby resetting the timer switch 294 and closing itsswitch contacts. The timer switch 294 remains in a reset condition untilthe relay 290 is deenergized at which time the contacts of the relay 290are connected to apply the voltage from battery 316 to the RUN terminalof the timer switch 294 which causes the timer switch 294 to run downfor a period of, for example, ten minutes whereupon its switch contactsopen. While the switch contacts of the timer switch 294 are closed,voltage from the battery 316 is applied via the closed contacts of thetimer switch 294 and the diode 300 to a terminal of the switch 214 sothat the operator has an interval of IO minutes during which time he mayturn the ignition key to close the switch 314 and start his automobilewithout taking the test.

It is also noted that the logic state of 1 at terminal B remains atterminal B until such time as the start switch 102 of the system 20A isturned OFF. To prevent the operator from utilizing this fact to cheat"the interlock system 284 by leaving the start switch 102 permanently inthe ON position, the timer switch 296 is employed. The timer switch 296which was reset by the pulse on line 312, begins to run for an intervalof, for example, 3 minutes after which its switch contacts open therebydisconnecting the terminal B from the ignition switch 314. Thus, even ifthe operator fails to turn off the system 20A, the system 20A isautomatically decoupled from the relay 290 three minutes after theinception of the test.

It is also apparent that there are times when it may be desirable tobypass both the interlock system 284 and the system 20A such as underemergency conditions when the operator may be too nervous to operate thesystem 20A. Accordingly, there is provided a switch 318 which shorts outthe contacts of the relay 290 thereby completing the ignition circuit286. The

switch 318 also has a set of contacts for simultaneously able sensor ofspeed not being shown in the figure.

A further feature of the interlock system 284 prevents the operator fromstarting his automobile if he has failed to pass the test in a number ofsuccessive attempts, for example, four such attempts. Each time theoperator operates the system 20A and fails the test, a logic state of 1appears at terminal C and advances the count of the counter 306 by onecount. The most significant bit (MSB) of the counter 306 attains a logicstate of 1 upon the occurrence of the fourth successive failure by theoperator in taking the test, the MSB being applied to the relay 292 aswell as to the timer 304. The MSB energizes the relay 292 therebydisconnecting the terminal B from the interlock system 284 so that evenif the operator later passes a test on the system 20A, still he will beunable to start the automobile until a sufficient period of time, suchas the twenty minutes provided by the timer 304, has elapsed. The outputof the timer 304 on line 319 is at a logic state of until such. time asthe timer 304 is energized by the MSB whereupon the output of the timer304 changes to a logic state of 1. This logic state of l is retainedwhile the timer runs down th rou gh the twenty minute interval whereuponthe logic state of 0 is restored on line 319. In the event that theoperator passes the test after one, two, or three failures, the passsignal having a logic state of 1 at terminal B is passed via the ANDgate 308 and the OR gate 310 to reset the counter 306 to a value of 0thereby ensuring that the terminal B will not be disconnected from theinterlock system 284 by the relay 292. In the event that the operatorfails the test for four or more attempts, in which case the counter 306may advance to a maximum count of seven, no further changes occur at theoutput MSB of the counter 306 until the conclusion of the minuteinterval at which time the timer 304 transmits a reset signal throughthe OR gate 310 to reset the counter 306 and thereby reconnect theterminal B with the interlock system 284.

Referring now to FIG. 6 there is seen an alternative embodiment of thegenerator 26 of FIGS. 1 and 3, identified by the legend 26A, whichtransforms (in a mathematical sense) the response of the person 30. Thegenerator 26A comprises an integrator 320 having one or two stages ofintegration. In FIG. 6 there is seen the potentiometer 174, previouslyseen in FIG. 3, connecting to the knob 46 with the output of thepotentiometer 174 being applied to the integrator 320. The output of theintegrator 320 is coupled to the comparator 32 previously seen in FIGS.1 and 3. The remaining portions of the system 20 and 20A are the sameand, accordingly, are not seen in FIG. 6. The effect of a single stageof integration in the integrator 320, such as may be provided by anoperational amplifier with capacitive feedback or an R-C circuit havinga long time constant, is to provide the person 30 of FIG. 1 with a ratecontrol. With a single stage of integration in the integrator 320, thehand motions of the person 30 must be equal to the derivative of thosehand motions utilized in the absence of the indicator 320. And with twostages of integration, his hand motions must be equal to the secondderivative of the motions utilized in the absence of the integrator 320.It may also be desirable to utilize a nonlinear network such as thatprovided by a diode in the vicinity of its break point, this being usedin lieu of the integrator 320 or, in conjunction therewith, by summingtogether the response of the diode and the integrator with a summingcircuit. By way of example, such a non-linear circuit 322 is shown inFIG. 6, the nonlinear circuit 322 comprising two diodes 324 and 326which are interconnected by a resistor 328, and an amplifier 330. Theanode electrode of the diode 324 is connected to the potentiometer 174.The cathode electrode of the diode 326 is connected to ground while theanode electrode of the diode 326 is connected to the amplifier 330 foramplifying the voltage appearing across the diode 326. A summing network332 is provided for summing together the output voltage of the nonlinearcircuit 322 and the integrator 320, with the output of the summingnetwork 332 being applied to the comparator 32.

It is understood that the above-described embodiments of the inventionare illustrative only and that modifications thereof will occur to thoseskilled in the art. Accordingly, it is desired that this invention isnot to be limited to the embodiment disclosed herein but is to belimited only as defined by the appended claims.

What is claimed is:

l. A system for analyzing the reactions of a person comprising:

means for providing a time dependent pattern relative to a preferredresponse of said person, at least a portion of said pattern representinga response having an amplitude which changes continually in a preferreddirection, said pattern being hidden from said person;

means coupled to said person for transmitting his response to saidsystem;

means for comparing said response to said pattern;

and

means for communicating to said person the comparison provided by saidcomparing means.

2. The system according to claim 1 further comprising means coupled tosaid comparing means for combining successive results of saidcomparisons.

3. The system according to claim 2 wherein said combining meansintegrates the results of said comparisons.

4. The system according to claim 3 further comprising means coupled tosaid combining means for determining when said integration signifies afailure on the part of said person to respond in accordance with saidpattern.

5. The system according to claim 4 further comprising means coupled tosaid determining means for indicating said failure to said person.

6. The system according to claim 5 further comprising means forindicating to said person that he has successfully responded to saidpattern, and wherein said determining means is coupled to said patternproviding means, said determining means energizing said successindicating means at a predetermined point of said pattern if there hasbeen no signifying of said failure.

7. The system according to claim 6 wherein said communicating meanselicits a sensory perception by said person, and said transmitting meanscomprises a handle operative by said person.

8. The system according to claim 7 wherein said pattern providing meanscomprises means operative by said person for restarting said patternindependently of the amount of said pattern which has already beenprovided by said pattern providing means.

9. The system according to claim 4 wherein said transmitting meansincludes means for transforming said response prior to said transmissionthereof, said transforming means varying the amplitude of said responsein a predetermined manner.

10. The system according to claim 9 wherein said transforming meanscomprises at least one integrator.

11. The system according to claim 9 wherein said transforming meansincludes means for varying the amplitude of said response in a nonlinearmanner.

12. The system according to claim 4 further comprising means coupled tosaid determining means for interlocking the circuitry utilized inoperating a vehicle.

13. The system according to claim 12 wherein said determining meansincludes means for signifying a success by said person in responding tosaid pattern.

14. The system according to claim 13 wherein said interlocking meanscomprises a relay having contacts connected to an ignition circuit ofsaid vehicle.

15. The system according to claim 14 wherein said interlocking meanscomprises means for counting the number of said failures, saidinterlocking means having circuitry responsive to said signifying ofsuccess by said determining means for energizing said relay when thenumber of said failures in a succession of such failures is below apredetermined number.

16. The system according to claim 15 further comprising means forlocking said relay in an energized position.

17. The system according to claim 16 wherein said relay locking meansincludes a timer for deactivating the locking circuit at the end of apredetermined time interval subsequent to the turning OFF of an ignitionswitch of said vehicle, said relay locking means having a circuitconfigured to permit the connection of said ignition switch therein,said relay locking means permitting energization of said relay by saidignition switch during said predetermined interval in the absence of asignal from said determining means.

18. The system according to claim 17 wherein said interlocking meanscomprises means for decoupling said determining means after apredetermined time interval subsequent to the beginning of said responseby said person.

19. The system according to claim 18 further comprising a switchingcircuit for bypassing said contacts of said relay, said switchingcircuit being coupled to a warning indicator of said vehicle forenergizing said indicator when said contacts are bypassed.

20. The system according to claim 1 wherein said pattern providing meanscomprises a staircase waveform generator and a filter coupled thereto.

21. The system according to claim 20 wherein said pattern providingmeans includes a'random signal generator for driving said staircasewaveform generator.

22. The system according to claim 21 wherein said staircase waveformgenerator comprises an UP/DOWN counter coupled to a digital-to-analogconverter.

23. The system according to claim 22 wherein said random signalgenerator comprises a random number generator, a clock, a switchingmeans and a counter, said clock driving said random number generator andsaid counter, said random number generator providing an address to saidswitching means for selecting an output of said counter, said switchingmeans applying said selected output to said UP/DOWN counter.

24. The system according to claim 4 wherein said pattern providing meanscomprises a charging circuit, switching means for varying the rate ofcharging of said charging circuit, and a timer for operating saidswitching means.

25. The system according to claim 24 wherein said comparing meanscomprises a differential amplifier having a first input connected tosaid charging circuit and a second input connected to said responsetransmitting means.

26. The system according to claim 24 wherein said differential amplifiercomprises a pair of coupled amplifier stages, said comparing meansfurther comprising a pair of serially connected transistors each ofwhich is coupled to a respective one of said amplifier stages, saidserially connected transistors providing a signal indicating that thesignal to one of said inputs of said differential amplifier is greaterthan the signal to the other of said inputs of said differentialamplifier.

27. The system according to claim 24 wherein said determining meanscomprises a first and a second threshold detector connected respectivelyto said timer and to said combining means, and an AND gate connected ina logical arrangement wherein a signal from said first detector ispassed bysaid AND gate in the absence of a signal from said secondthreshold detector for indicating that said person has succeeded in hisresponse, a signal from said second threshold detector indicating afailure of said response while disabling said AND gate frompassing theoutput signal of said first threshold detector.

28. In combination:

means adapted to be coupled to an organism for pro viding a response bysaid organism;

means for generating a pattern relative to a preferred response of saidorganism, at least a portion of said pattern representing a responsehaving an amplitude which changes continually in a preferred direction,said pattern being hidden from said organism;

means for comparing said response to said pattern;

and

means for communicating to said organism the comparison provided by saidcomparing means.

29. The combination according to claim 28 further comprising means forinterlocking said communication means with a vehicle to be operated bysaid organism, said interlocking means preventing operation of saidvehicle when said response compares poorly to said

1. A system for analyzing the reactions of a person comprising: meansfor providing a time dependent pattern relative to a preferred responseof said person, at least a portion of said pattern representing aresponse having an amplitude which changes continually in a preferreddirection, said pattern being hidden from said person; means coupled tosaid person for transmitting his response to said system; means forcomparing said response to said pattern; and means for communicating tosaid person the comparison provided by said comparing means.
 2. Thesystem according to claim 1 further comprising means coupled to saidcomparing means for combining successive results of said comparisons. 3.The system according to claim 2 wherein said combining means integratesthe results of said comparisons.
 4. The system according to claim 3further comprising means coupled to said combining means for determiningwhen said integration signifies a failure on the part of said person torespond in accordance with said pattern.
 5. The system according toclaim 4 further comprising means coupled to said determining means forindicating said failure to said person.
 6. The system according to claim5 further comprising means for indicating to said person that he hassuccessfully responded to said pattern, and wherein said determiningmeans is coupled to said pattern providing means, said determining meansenergizing said success indicating means at a predetermined point ofsaid pattern if there has been no signifying of said failure.
 7. Thesystem according to claim 6 wherein said communicating means elicits asensory perception by said person, and said transmitting means comprisesa handle operative by said person.
 8. The system according to claim 7wherein said pattern providing means comprises means operative by saidperson for restarting said pattern independently of the amount of saidpattern which has already been provided by said pattern providing means.9. The system according to claim 4 wherein said transmitting meansincludes means for transforming said response prior to said transmissionthereof, said transforming means varying the amplitude of said responsein a predetermined manner.
 10. The system according to claim 9 whereinsaid transforming means comprises at least one integrator.
 11. Thesystem according to claim 9 wherein said transforming means includesmeans for varying the amplitude of said response in a nonlinear manner.12. The system according to claim 4 further comprising means coupled tosaid determining means for interlocking the circuitry utilized inoperating a vehicle.
 13. The system according to claim 12 wherein saiddetermining means includes means for signifying a success by said personin responding to said pattern.
 14. The system according to claim 13wherein said interlocking means comprises a relay having contactsconnected to an ignition circuit of said vehicle.
 15. The systemaccording to claim 14 wherein said interlocking means comprises meansfor counting the number of said failures, said interlocking means havingcircuitry responsive to said signifying of success by said determiningmeans for energizing said relay when the number of said failures in asuccession of such failures is belOw a predetermined number.
 16. Thesystem according to claim 15 further comprising means for locking saidrelay in an energized position.
 17. The system according to claim 16wherein said relay locking means includes a timer for deactivating thelocking circuit at the end of a predetermined time interval subsequentto the turning OFF of an ignition switch of said vehicle, said relaylocking means having a circuit configured to permit the connection ofsaid ignition switch therein, said relay locking means permittingenergization of said relay by said ignition switch during saidpredetermined interval in the absence of a signal from said determiningmeans.
 18. The system according to claim 17 wherein said interlockingmeans comprises means for decoupling said determining means after apredetermined time interval subsequent to the beginning of said responseby said person.
 19. The system according to claim 18 further comprisinga switching circuit for bypassing said contacts of said relay, saidswitching circuit being coupled to a warning indicator of said vehiclefor energizing said indicator when said contacts are bypassed.
 20. Thesystem according to claim 1 wherein said pattern providing meanscomprises a staircase waveform generator and a filter coupled thereto.21. The system according to claim 20 wherein said pattern providingmeans includes a random signal generator for driving said staircasewaveform generator.
 22. The system according to claim 21 wherein saidstaircase waveform generator comprises an UP/DOWN counter coupled to adigital-to-analog converter.
 23. The system according to claim 22wherein said random signal generator comprises a random numbergenerator, a clock, a switching means and a counter, said clock drivingsaid random number generator and said counter, said random numbergenerator providing an address to said switching means for selecting anoutput of said counter, said switching means applying said selectedoutput to said UP/DOWN counter.
 24. The system according to claim 4wherein said pattern providing means comprises a charging circuit,switching means for varying the rate of charging of said chargingcircuit, and a timer for operating said switching means.
 25. The systemaccording to claim 24 wherein said comparing means comprises adifferential amplifier having a first input connected to said chargingcircuit and a second input connected to said response transmittingmeans.
 26. The system according to claim 24 wherein said differentialamplifier comprises a pair of coupled amplifier stages, said comparingmeans further comprising a pair of serially connected transistors eachof which is coupled to a respective one of said amplifier stages, saidserially connected transistors providing a signal indicating that thesignal to one of said inputs of said differential amplifier is greaterthan the signal to the other of said inputs of said differentialamplifier.
 27. The system according to claim 24 wherein said determiningmeans comprises a first and a second threshold detector connectedrespectively to said timer and to said combining means, and an AND gateconnected in a logical arrangement wherein a signal from said firstdetector is passed by said AND gate in the absence of a signal from saidsecond threshold detector for indicating that said person has succeededin his response, a signal from said second threshold detector indicatinga failure of said response while disabling said AND gate from passingthe output signal of said first threshold detector.
 28. In combination:means adapted to be coupled to an organism for providing a response bysaid organism; means for generating a pattern relative to a preferredresponse of said organism, at least a portion of said patternrepresenting a response having an amplitude which changes continually ina preferred direction, said pattern being hidden from said organism;means for comparing said response to said pattern; and means Forcommunicating to said organism the comparison provided by said comparingmeans.
 29. The combination according to claim 28 further comprisingmeans for interlocking said communication means with a vehicle to beoperated by said organism, said interlocking means preventing operationof said vehicle when said response compares poorly to said pattern.